The present invention relates to a computer-aided three-dimensional modeling system, and more particularly, to improvements for checking drawings for three-dimensional models.
In recent years, design drawings have changed from two-dimensional drawings to direct three-dimensional (hereinafter referred as “3-D”) modeling or 3-D models. According to the conventional two-dimensional system, if a product is made into a shape not intended, the drawing is eventually referred to for a correct shape, and the shape can be read based on the size or drawing rules. Therefore, the product can eventually be produced as designed. In the 3-D system, however, a designed model is directly used in the succeeding process (working process), and an incorrect shape is reflected in the product. Therefore, checking drawings in the design step is crucial. If the succeeding process is not fully taken into account in the step of designing a 3-D model, an unexpected correction might be necessary, which could increase the manufacturing cost.
More specifically, when a designed model for a resin molded product or other molded products is produced, the manufacturing cost for the mold could be increased if modeling is carried out without taking into account elements in the succeeding process such as how to produce the mold or the structure of the mold. Fillet surfaces (rounded corners) or ribs drawn thoughtlessly to be too small or thin for example might not allow machining when a mold is manufactured, and electric discharge machining or even manual handling might be required.
According to conventional two-dimensional designing, a mold designer, for example, reads the shape based on the drawing in the succeeding process, and makes a judgment (for example, about which manufacturing method to employ). At the time, the designer is notified of any special working required, and therefore there is little problem in that connection. According to the 3-D system, however, a model produced by a designer is used “as is” for a mold model, and therefore the details of the shape must be checked. Practically speaking, however, it would be impossible for the designer to consider entirely how to design the mold when producing a design model.
It takes a lot of time to check whether or not each part of a 3-D model is produced as intended by the design. There is a high likelihood that a mistake will occur. It is particularly difficult to find errors related with fillet surfaces or chamfers that tend to be easily omitted in drawings.